heptapeptide comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-01-04. Numbers and descriptions here follow the published literature rather than marketing material.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised solid form |
| Solubility class | Freely soluble in water | Hydrophilic heptapeptide |
| Dry storage temperature | -20 degrees Celsius or lower | Sealed, desiccated, protected from light |
| Solution storage | 2 to 8 degrees Celsius short term | Avoid repeated freeze-thaw cycles |
| Common identification method | Reversed-phase HPLC with mass spectrometry | Confirms purity and molecular mass |
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
==== Der Zweite Weltkrieg und die Folgen ==== Ab Mai 1945 gehörte die Stadt Liberec zur wiedererrichteten Tschechoslowakei. Ab dem Mai 1945 wurde die deutschsprachige Bevölkerung mehrheitlich enteignet und vertrieben. Andere flüchteten vor Misshandlungen und Abtransport in Sammellager unter Zurücklassung ihres Eigentums. Das private und öffentliche Vermögen der deutschen Bevölkerung in der Tschechoslowakei wurde durch das Beneš-Dekret 108 konfisziert, das Vermögen der evangelischen Kirche durch das Beneš-Dekret 131 liquidiert, und die katholischen Kirchen wurden in der kommunistischen Ära enteignet. Die Patenschaft für die Heimatvertriebenen aus Reichenberg übernahm 1955 Augsburg, wo in der Heimatstube Reichenberg ein Erinnerungsarchiv aufgebaut wurde und der „Heimatkreis Reichenberg – Stadt und Land e. V.“ in Augsburg mit seinen Initiativen im Jahre 2001 zur Städtepartnerschaft von Augsburg und Liberec führte. Die Reichenberger Zeitung, das „Jeschken-Iser Jahrbuch“ und das „Reichenberg Heimatblatt“ des Helmut Preußler Verlags in Nürnberg fördern diese völkerverbindende Partnerschaft im Sinne des vereinten Europas. Im Jahre 1947 hatte Liberec 52.798 Einwohner. Zahlreiche Neubürger aus Mittelböhmen, der Slowakei, sogenannte Repatrianten und Roma siedelten sich in der Nachkriegszeit in Liberec und den Nachbarorten an.
==== Prager Frühling ==== Während der Niederschlagung des Prager Frühlings durch Truppenverbände des Warschauer Pakts gab es am 21. August 1968 in Liberec Todesopfer unter der ortsansässigen Bevölkerung, als diese gegen die sowjetischen Okkupationstruppen demonstrierte und von einem Schützenpanzerwagen aus das Feuer auf die vor dem Rathaus versammelten Menschen eröffnet wurde. Eine Gedenktafel mit neun Gliedern einer Panzerkette an der Vorderfront des Rathauses erinnert heute an die Toten. Die Demonstranten leisteten im Wesentlichen gewaltfreien Widerstand, so nutzten sie z. B. Lücken in den Marschkolonnen der Okkupationstruppen aus, um an Kreuzungen in der Stadt und der Umgebung die Panzerkonvois in falsche Richtungen umzuleiten, damit diese die Orientierung verlieren. Am 23. August 1968 waren deshalb viele Straßenschilder der Innenstadt von Liberec ausgetauscht. Fast jede Straße hieß nun „Dubčekova ulice“ – auch, um die Verbundenheit mit Parteichef Alexander Dubček zu zeigen. Auf der Spitze des Rathausturms entfalteten Kletterer eine große schwarze Fahne. Erinnerungen an den Roman Der brave Soldat Schwejk von Jaroslav Hašek sollten geweckt werden.
==== Samtene Revolution ==== Am 17. November 1989 kam es wie auch in anderen Gebieten der Tschechoslowakei in Liberec zu großen Protesten gegen das sozialistische Regime, die in der Samtenen Revolution mündeten. Nach dem Wechsel von der sozialistischen Planwirtschaft zur liberalen Marktwirtschaft von 1989 begann eine Neuorientierung der Stadt Liberec. Investoren zeigten Interesse an einem Wiederaufbau. Das historische Zentrum der Stadt wurde renoviert und die Infrastruktur verbessert. Dabei wurde die alte meterspurige Straßenbahn auf Regelspur (teilweise mit Dreischienengleis) umgebaut. Die Textilfabrik Textilana fiel allerdings den verschärften Wettbewerbsbedingungen zum Opfer und wurde 2004/2005 fast völlig abgerissen. Ein wichtiger Industriezweig war das LIAZ-Werk auf dem Gemeindegebiet von Jablonec, wo bis 2003 Lkw produziert worden sind. Hauptprägend für die ehemalige Industriestadt Liberec ist mittlerweile eher Gewerbe in Form von Einzelhandel und Dienstleistungen. So entstanden im Stadtzentrum und am Stadtrand mit neu erschlossenen Gewerbegebieten zahlreiche neue Einkaufszentren, die von der Nähe zur deutschen Grenze profitieren. Für das nahe Automobilwerk Mladá Boleslav bestanden bereits zahlreiche Zulieferer, die 1990 durch Privatisierungen zu internationalen Großkonzernen gelangten.
Sources: de.wikipedia.org
== Städtepartnerschaften == Niederlande Amersfoort, Niederlande (1996) Frankreich Amiens, Frankreich Deutschland Augsburg, Deutschland (2001) Israel Nahariya, Israel (1994) Deutschland Zittau, Deutschland (2004) Siehe auch die internationale Partnerschaft der Reichenberger Region, wovon Liberec die Hauptstadt ist.
Sources: de.wikipedia.org
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.
Reversed-phase HPLC establishes purity, while mass spectrometry confirms the expected molecular mass. Sequence confirmation may use tandem mass spectrometry or peptide mapping. A certificate of analysis typically reports these results alongside the analytical method applied.
In Russia it is a registered medicine available by prescription. In many other countries it is not approved for human use and is supplied only as a research chemical. Import and possession rules differ by jurisdiction, and buyers are responsible for checking local requirements.
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.